1. Field of the Invention
The disclosure relates generally to calculation methods for calculating white balance correction values, and, more particularly to calculation methods for calculating white balance correction values applied in an image capture device while using an auxiliary light for shooting pictures/capturing images.
2. Description of the Related Art
Charge-coupled devices (CCD) and Complementary Metal-Oxide Semiconductors (CMOS) have been widely used as image sensors in digital cameras in replace of conventional film. During picture shooting/image capturing, color accuracy determined by the image sensor for the image, may be impacted by the color temperatures of the lights coming from various light sources surrounding the image, as the brightness of the captured environment is provided by the surrounding lights intermixed with various light sources.
Typically, when capturing an image within a light source with lower color temperature value, image color for the captured image will slant toward the red color. Contrarily, the image color for the captured image will slant toward the blue color when capturing an image within a light source with higher color temperature value. Therefore, under light sources with different color temperature values, the image color for the captured image will be somewhat different from that of the actual object so that the color for the captured image should be corrected. Such correction process for correcting the image color is called a white balance process.
When capturing an image within an environment with low brightness, a flash is usually used to compensate for the lack of brightness. Methods for performing the white balance process using the flash, such as US publication No. 20030030730 A1, have already been disclosed. Meanwhile, US publication No. 20030030730 A1 provides a method for adjusting the white balance using the flash, in which, in the invention, a first control value is obtained based on the flash amount shot to the target object and the brightness before shooting. The first control value is applied to a default formula to obtain a second control value, and a white balance process for the image signals outputted by the image sensor is then performed according to the first control value and the second control value. However, the greater the color strength of the provided flash becomes, the larger the effect for color deviation.
Therefore, to overcome the aforementioned disadvantages, a calculation method for calculating the white balance correction values is provided by using the brightness weightings provided by the environment light and the auxiliary light when capturing the image so as to efficiently improve the color deviation effect caused by the auxiliary light source.